New Delhi: Bahujan Samaj Party (BSP) chief Mayawati today stunned the Rajya Sabha when she criticised Vice President Hamid Ansari in the House, accusing him of dereliction of duty.

Unrepentant, she then said that her criticism of Mr Ansari was "a tough first step" to alert the government to more serious consequences if it does not urgently push through a law to reserve promotions in government jobs for Dalits and tribals.

Mr Ansari, who is also the Chairman of the Rajya Sabha, had observed yesterday that the "Chair of the House is forced to watch helplessly" as MPs shout and disrupt proceedings.

Ms Mayawati, who is one such Rajya Sabha MP, lashed out at the Chair today saying, "Over the last few days, the House is not allowed to function after 12 pm. It is your responsibility to ensure that it functions." She added, "You are not seen here after 12 pm. What kind of House is this?"

It is parliamentary tradition that the Chair is never questioned by a member on how it conducts the House.

A visibly shocked Mr Ansari urged, "You are a senior leader... the House is run with the cooperation with everyone. The House is running right now. You please allow the House to run," he told Ms Mayawati, who did not oblige. Her MPs raised slogans, forcing Mr Ansari to adjourn the House for some time.

The Rajya Sabha has been paralysed this week largely over the issue of a discussion on whether promotions in government jobs should be reserved for Dalits and tribals.

Mayawati insists the proposal must be exigently discussed and introduced as law; her rival from Uttar Pradesh, Mulayam Singh Yadav, aggressively disagrees. His MPs have threatened to disrupt the Rajya Sabha every day, if needed, to prevent a debate on the "quota bill."

While the proposal would be welcomed by Mayawati's vote bank, it's likely to cause resentment among the backward caste and Muslim voters of Uttar Pradesh who have traditionally supported Mr Yadav's Samajwadi Party.

Last week, both Mayawati and Mr Yadav rescued the government during a tough vote on its retail reform, which allows supermarkets like Wal-mart into India. In return for her party's votes, Mayawati had made it clear that the quota bill must be enacted as law.